Title: Correlation of QTc Interval and Outcomes After Methadone Overdose
题目：QT间期与美沙酮过量使用后果的关系
Author 作者: Bryan Hayes
翻译：步涨 校对：陈都，肖锋

Methadone prolongs the QTc interval. Is the degree of QTC widening correlated to worse outcomes after overdose?
美沙酮会使QT间期延长。而QT间期延长的程度是否与其过量使用后更坏的结局有关呢？
A new study demonstrated the ability of triage QTc to predict death, intubation, and respiratory arrest showed thresholds of 470, 447.5, and 450 ms with sensitivity (95 % CI) and specificity (95 % CI) of 87.5 (47.3-99.7), 86.8 (74.7-94.5), and 77.3 (62.2-88.5), respectively.
一项研究表明，美沙酮过量后，QT间期延长至470、450及447.5毫秒后，患者死亡、插管及呼吸停止的预测的敏感性及特异性（95% 可信区间）分别为；87.5 (47.3-99.7), 86.8 (74.7-94.5), 及 77.3 (62.2-88.5)。
Application to clinical practice: QTc interval prolongation has the potential to help predict outcomes after methadone overdose, but the QTc thresholds in this study were really not that prolonged. Patients on chronic methadone without overdose have baseline QTc intervals longer than those in the study after overdose. Many factors contribute to the ultimate disposition of methadone overdose cases.
临床应用：QT间期延长具有有助于美沙酮过量所致后果的预测。但是在该研究中，QT间期阈值并不能算作明显延长。长期慢性但非过量使用美沙酮的患者，其QT间期的基线较本研究中过量使用后的更长。许多因素对美沙酮过量使用的最终转归都有影响。
References 参考文献：
Farsi D, et al. The correlation between prolonged corrected QTc interval with the frequency of respiratory arrest, endotracheal intubation, and mortality in acute methadone overdose. Cardiovasc Toxicol 2014 May 9. [Epub ahead of print] [PMID 24811951]